The present invention relates to a method and a device for operating a machine tool.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
In order to reliably prevent collisions, the machining time and the freedom from errors in parts programs for manufacturing workpieces by machine tools, it has become increasingly common to simulate parts programs, which include a model of the real machine tool, prior to the actual real machining operation on the real machine tool. Only after the simulation has been carried out successfully is the parts program transferred to the real machine tool, and the machining operation is controlled using the parts program.
However, the simulation can only provide additional safety with respect to the criteria of absence of collisions, machining time and freedom from errors if the configuration of the modeled machine tool in the simulation conforms to the actual configuration of the machine tool, i.e., the actual configuration of the real machine tool present at the time of the machining operation.
Examples for such a configuration are:    1. tool-equipment data, for example in form of tool dimensions, tool holder geometries and magazines used in the tool change,    2. blank data, such as the position and geometry of the blank,    3. tool clamping piece data such as the position and geometry of the clamping pieces for clamping the blank,    4. software configuration, for example in form of control software version and/or parameterizations of the control and drives.
The confidence instilled by the “successful” simulation in the quality of the parts program tested by such means, and the demand for ever faster production times, often causes in practice further tests on the real machine tool (for example, carrying out the machining operation with a markedly reduced feed) to be eliminated. However, the actual configuration, i.e. the configuration of the machine tool actually present at the time of the pending machining operation, often does not correspond to the configuration used in the simulation (referred to below as the simulated configuration). In a worst case scenario, a “successfully” simulated parts program may therefore still cause damage to the real machine tool or costly workpiece rejects. Additionally, incorrectly calculated machining times lead to a deterioration in the ability to plan cycle times and machine movements.
It would therefore be desirable and advantageous to develop an improved method and a device for operating a machine tool to obviate prior art shortcomings and to avoid, during a machining process, faults caused when the configuration of the machine tool used to simulate the parts program does not conform to the configuration of the real machine tool during the real machining operation.